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Red-breasted Merganser

Mergus serrator

The red-breasted merganser is a diving duck with a long, serrated bill and a shaggy crest on the back of the head. It lives along the shores of the Chesapeake Bay and its tidal creeks and rivers from autumn through spring.


  • Shaggy crest on the back of the head
  • Long, slender, reddish-orange bill with serrated edges
  • White wing patches (called specula)
  • Males and females have different patterns and coloring
  • Males have a greenish head; a white collar; a reddish-brown chest; and gray sides
  • Females have a reddish-brown head and neck, and a shorter crest and lighter chest than males
  • Grows to 20-25 inches long


  • Lives on shallow waters along the shoreline and tidal wetlands of the Chesapeake Bay and its creeks and rivers
  • Flocks also common on open portions of the Bay and its rivers in winter


  • Visits the Bay region from autumn through spring
  • Migrates to its northern breeding grounds in mid-March


  • Eats mostly fish such as killifish, menhaden and anchovies
  • Hunts in mixed gender groups in the Bay’s shallows. Groups herd schools of fish and then feed on them underwater.
  • Uses its unique serrated bill to catch slippery fish underwater


  • Humans hunt red-breasted mergansers
  • Owls and red foxes may prey upon adults
  • Minks, gulls and ravens prey upon eggs and young on their breeding grounds


  • Takes off by running across the water’s surface and flapping its wings
  • Flies in a single-file line very low over the water
  • In flight, all mergansers hold their bill, head, body and tail straight
  • Can be identified in flight by its white wing patches, long reddish bill and white neck (on males)


  • Usually silent in winter, when it is not breeding season
  • During courtship rituals, males may make a yeow-yeow sound, and females may respond with a raspy krrrr-krrrr

Reproduction and Life Cycle:

  • Does not reproduce in the Bay region
  • Nests and breeds from the Great Lakes to the Arctic
  • Returns to the same nesting site every year
  • Only 50 percent of all red-breasted mergansers are believed to survive winter and migration each year
  • Can live as long as nine years

Other Facts:

  • Very active swimmers that can swim well both above and below the water’s surface. Like other diving ducks, red-breasted mergansers are awkward on land because their legs are located far back on the body.
  • Can stay underwater for as long as 44 seconds

Sources and Additional Information:


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